Introduction of UV-cured interpenetrating polymer network in PEO-based all-solid-state Li-S battery

Abstract

Lithium–sulfur (Li-S) battery attracts numerous study due to its high theoretical specific capacity. Unfortunately, the notorious shuttle effect and the safety issue of lithium anode limit the development. The application of solid-state electrolyte is regarded as one of the solutions. Herein, a UV-cured polymer network is introduced in poly(ethylene oxide) (PEO)-based solid polymer electrolyte (SPE) to enhance the performance of Li-S battery. Poly(ethylene glycol) dimethacrylate (PEGDMA) was used as the main crosslinking monomer. The abundant -C-C-O- long chain can provide a fast channel for Li+ transfer. Trimethylolpropane ethoxylate triacrylate (TMPETA) is used as the crosslinker, which made the linear copolymer formed by single monomer transform into interpenetrating polymer network. Hence, an interpenetrating UV-cured network was synthesized and combined with PEO. This elaborately designed structure enhances the ionic conductivity and the mechanical properties of PEO SPE as well as hinder the lithium polysulfides (LiPSs) migration. As a result, the symmetric Li cells with this SPE can stably cycle for >1600 h at the current density of 0.1 mA cm−2. Moreover, the Li-S cells can deliver an initial capacity of 1131 mAh g−1 at 0.1C. It provides a thread to design the polymer network of SPE.